Background: In recent years antioxidants, foods rich in antioxidants (e.g. fruits, vegetables) and fish have been suggested to protect against chronic obstructive pulmonary disease (COPD). There are also indications for a protective effect of whole grain intake and of consuming moderate amounts of alcohol. It is, however, not clear whether the effects of the different dietary factors on COPD are independent of each other and if so, whether their effects are additive.
Objective: To gain more insight into the potential protective effect of diet on COPD, we studied fruit, vegetable, fish, alcohol and whole grain consumption simultaneously in relation to pulmonary function and COPD symptoms.
Methods: Analysed were cross-sectional data collected in 13 651 men and women aged 20-59 years participating between 1994 and 1997 in the MORGEN study (monitoring project on risk factors and health in The Netherlands). Regression models were adjusted for age, gender, height (for pulmonary function only), smoking, BMI and energy intake.
Results: Fruit and whole grain intake showed independent beneficial associations with COPD (P-trend < 0.001). Furthermore, in subjects with low alcohol consumption (1-30 g/day) the forced expiratory volume in 1 s (FEV1) was higher and the prevalence of COPD symptoms lower than in non-drinkers (P < 0.001). The effects of a favourable intake of fruits (> 180 g/day), whole grains (> 45 g/day) and alcohol (1-30 g/day) were largely additive. In the 2998 subjects with a favourable intake of the three foods, the FEV1 was 139 mL higher and the prevalence of COPD symptoms lower (odds ratio (OR) = 0.44) than in subjects (n = 1406) with unfavourable intakes of fruits, whole grains and alcohol (P < 0.001). A similar effect was observed in those who had never smoked. Fish and vegetable intake did not show independent beneficial associations with COPD.
Conclusions: Our results suggest independent beneficial effects of fruits, whole grains and alcohol on COPD that are largely additive and cannot be explained by smoking habits.